Slashdot videos: Now with more Slashdot!

View

Discuss

Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

anthemaniac writes "Astronomers have long suspected that water should exist in the atmospheres of extrasolar planets. Now they have evidence. Water has been discovered in a planet called HD209458b, which was previously found to have oxygen. From the article: 'The discovery ... means one of the most crucial elements for life as we know it can exist around planets orbiting other stars.' But don't go looking for little green men. You might remember HD209458b as a 'hot Jupiter' that boils under the glow of its very nearby star."

This discovery only reinforces the possibility of life outside our solar system; we've only discovered a few extra-solar planets, and at least one among those we've seen has life. So:

How many people now think that ETs of some form do exist?

It's a big universe. Chances are very good that other life of some sort exists. However, we have found no evidence of life yet, despite the presence of oxygen which would usually be considered a strong indicator of the presence of life.

Actually, in areas of greater pressure (deeper under the clouds), there is still the possibility of life I would say.

Another thing is, we often make the following assumptions in terms of life forms, and we can be ceratain of none of them:

1) requirements of Carbon and Oxygen-- Sulphur, Silicon, and any far-left or far-right non-noble element can handle the requirements here (namely something that can form long complex structures, and something highly reactive that nonetheless has stable compounds wherein it exists)2) The life will be based on nucleic acids (RNA/DNA) and amino acids (proteins)-- While these are more simple structures that could perform their tasks while remaining stable, there are other structures that could potentially store data and perform structural/chemical tasks.

I think that most scientists are aware of that and what they're actually getting at are planets that could support life similar to our own. Life that we could recognize and interact with, perhaps even coexist with in some unknown future. There are many unproven forms that life can exist in, however we probably wouldn't recognize them if we saw them so we naturally stick with what we know.

What right do we need to exploit the universe for our own benefit ? The fact that it's there and we are able to exploit it are reason enough, luckily it's a part of human nature to explore our surroundings and make use of what we find so despite what you might want it's almost inevitable that this is what will happen.Humans have managed to co-exist with each other for hundreds of thousands of years without any real problems so it's perfectly likely we could achieve the same harmony with other intelligent sp

In Cosmos, Carl Sagan has described such beings(hypothetical beings - if you want to nitpick), consider them to be similar to large gas bags, that feed on carbon matter in the atmosphere. If you consider it that flying whales post might actually describe them pretty well
also - Such creatures were used by Arthur C. Clarke in one of his oddesy series books (forget which one), he even described a predator of sorts for them, interestingly for another descrpition (although not at all based on science or facts

The Slylandro in Star Control II were like that as well -- a sentient gas giant species. They developed their intelligence not from toolmaking but from cooperative hunting, chasing small organisms into storm vortices much in the same way that whales use bubbles to trap krill into a bait ball. The more intelligent, cooperative Slylandro were able to thrive in more inhospitable areas and capture more elusive prey. However, after reaching sentience, their culture stagnated. Having no ability to make tools,

(warning, I use chemical symbols. You might want a periodic table).
I agree with you that there could well be life that is vastly different than what we are used to.

Another thing is, we often make the following assumptions in terms of life forms, and we can be ceratain of none of them:
1) requirements of Carbon and Oxygen
-- Sulphur, Silicon, and any far-left or far-right non-noble element can handle the requirements here (namely something that can form long complex structures, and something highly reactive that nonetheless has stable compounds wherein it exists)

But this doesn't make sense to me. When you say far-left and far-right, I assume you mean the periodic table. That means you are talking about Cl, Br, Na, K, etc. That doesn't make sense (they tend to only make 1 bond), so I figure you are talking about the p-block.
That means you are talking about B, F, C, Si, Cl and Br. What is special about carbon is that it forms 4 bonds. So, this means you are just talking about carbon and silicon. Let's throw out anything heavier (Ge, Sn) because they aren't that abundant.
Sure, there could be something based on silicon but... Look at CO2 (a gas) and SiO2 (silica, a solid). Carbon just seems like the best candidate for life to be based on. Nitrogen (or P) and boron (or Al) seem to be the best other candidates.

That's a misconception; the sort of silicon-based life that we're talking about are not precisely the same as carbon chains. In carbon chains, you typically have C-C-C-C-C... etc. In the equivalent silicon (actually silicone) molecule, you have Si-O-Si-O-Si-O-Si.... etc. Si-Si-Si... etc doesn't chain well, but Si-O-Si-O.. chains indefinitely. Compare a hydrocarbon-based lubricant with a silicone-based one, hydrocarbon solids (plastics) with silicone ones, etc. There's been a lot more research on the former so far; the latter can likewise be functionalized.

A few differences in the chemistry:

1) C-C-C-C-C... chains can freely rotate, while Si-O-Si-O... chains need a specific "joint" to do so.2) Carbon more readily double and triple bonds, although removing Os from the Si-O chain can create similar (but not equivalent) effects.

There are all sorts of biologically interesting silicon compounds. The silicon equivalent of methane is silane. It's even more flammable than methane; it's hypergolic with our atmosphere (burns on contact). Its giving up of its hydrogen could be seen as equivalent to ATP and its phosphorus. Longer "silanes" scale like longer hydrocarbons -- their vapor pressure decreases the longer they get (silanes with 2-3 silicons make for good wood sealants). Zeolites are silicates (your typical silicon solids that you were picturing) but with various metal ions interspersed with them; they're excellent, highly selective catalysts. Probably the most biologically interesting (to me, at least) are silanols [ic.ac.uk], which exist naturally in Earth's oceans (and probably predated life), and can form all sorts of catalytic groups, membranes, etc.

The key seems to be evolution in a reducing atmosphere. Moderately low temperature, high pressure, and acidic would be good -- perhaps a subsurface ocean, like on Europa or Enceladus around a geothermal vent, not too close to the heat. The first requirement is abiotic production of silicone chains; these will naturally break down into silanols. Here's one possibility: volcanic hydrochloric acid reacts with silicon to produce cholorosilanes, which polymerize in the presence of water. These break down int

The problem with silanes is lack of stable aromatic compounds - carbon seems to be unique in that sense, AFAIR. Si atoms just have a lot more degrees of freedom - they don't hybridize, they just oxidize/reduct.

Well, let's look at what the most common elements are in the universe. A quick Google shows:Hydrogen, helium, oxygen, carbon, neon, iron, nitrogen, silicon, magnesium, sulfur. There's your top ten, in that order. It's interesting that carbon, versatile as it is, is so very common. Considering that hydrogen and oxygen, hence water, rank even higher, I think that life as we know it has statistically higher odds of appearing, especially in conditions where water is liquid. The physics of these compounds i

I agree as for sulfur but silicon is stretching things a bit. In contrast to carbon, silicon dioxide is a non soluble solid. The gaseous solublity properties of carbon means that it can distribute in water and in cells where it can be fixed into sugars and biological compounds by life. Silicon can't be distributed that way and thus least likely to be the basis of life. There are other reasons [wikipedia.org] however it is suffice to say that silicon based life would have a smaller occurrence in the universe than that of ca

Sulphur, Silicon, and any far-left or far-right non-noble element can handle the requirements here (namely something that can form long complex structures, and something highly reactive that nonetheless has stable compounds wherein it exists)

There is a good chance, but it would most likely be microbial life (ie bacteria)...not something exciting like little green men. Bacteria can grow in soil, acidic hot springs, radioactive waste and in extreme cold condiations (ie space)...

anyone who doubts that there is ET life is either extremely ignorant or just a fool. seriously, i don't even see how in this day in age that there is even a debate about 'if?'. the real questions are 'what kind?', 'where?', 'how "intelligent"?'. we've known for some time now that new elements get created with every star and spread with their explosions and comets carry the ingredients for life light years way.
Comets are intergalactic sperm, planets/moons are the eggs. In my mind it couldn't be more ob

Comets, in general are not interstellar bodies, much less intergalactic. Is it probable that a comet deposited the necessary elements on Earth for life? Yes, but those comets were created during the creation of our solar system; they didn't come from Alpha Centauri, etc. I also believe, just on odds, that there is other, probably intelligent, life in the universe and your questions are more accurate than "If"

I'm a Christian, and I find your argument ad hominem, off topic, and ignorant at best. If you aren't trolling, please keep in mind that a belief in a God, although shared by crazies and extremists, does not make one any less intellectually capable, any more than being a vegetarian makes a person evil because Hitler was one.

Maybe you should redirect your anger to all your fellow Christians who believe exactly as I said in my post. I'm just posting on my observations on the great majority of Christians in this country and how they behave.

Your Hitler comparison is flawed. Hitler was only one person, and most vegetarians are nothing like Hitler. However, a majority of Christians (at least in the USA; my apologies if you live somewhere else where Christians are not fundamentalist) do believe the earth is 6000 years old, that evolution is false, that Creationism should be taught in public schools, etc. So if you're one of the rare minority that doesn't believe this way, and doesn't try to push these beliefs on everyone else, then that's great. But you have to acknowledge that most of your co-believers are like this this.

I disagree. While the ones with media time are certainly a little more extreme (or else we'd have mobs of them in the streets demonstrating), most of the others, while more passive, actually support most of their positions. See the recent polls which found that 48% of Americans don't believe in Evolution. That's an indicator that, yes, tens of millions of people in the USA are in agreement with these so-called extremists. Heck, even here on Slashdot, "news for nerds", we have a very large contingent of

You're absolutely wrong. If you don't believe me, here's a link to one of the aforementioned polls:CBS poll [cbsnews.com]

Before you say anything about the validity of polls, I think they're a lot more valid than some comments from random people like you on Slashdot who are trying to defend a position with no evidence whatsoever.

So your assertion that most Christians in the USA ("WHEREVER" is a totally different ball of wax; other places don't have nearly as many fundamentalists as the USA) "DONT WANT" creationism taught in school is obviously false. The percentage of Christians in the USA is certainly significantly less than 100%, with all the atheists, agnostics, Muslims, Jews, Hindus, and others. Let's say it's around 75% for argument's sake; if 65% out of 75% believes both Creationism and Evolution should be taught, that's obviously a majority. And the 37% of the stricter Creationism-only group is still about half. Again, look at the significance here: HALF of US Christians want Creationism (only) taught in schools.

So no, my opinions are not based on any personal anecdotes, but instead large nationwide surveys.

Whoops, I guess that was a little unclear, although the linked article actually presents it that way from the poll results. I imagine the poll questions were presented separately, with one being "status quo or creationism + evolution?" and the other being "status quo or creationism-only?". The strict creationists would choose the latter for both questions.

On what basis are you saying this? It doesn't simply follow from the universe being big if the chances of life appearing at any given location is small enough. How do you know that this isn't the case?

Because we know it exists in at least one location, and given the size of the universe, the odds are pretty good that the EXACT same conditions exist in at least one other place. Do you have any idea how many billions of stars are in our galaxy, and how many billions of galaxies are in the observable universe?Certainly no one knows the exact odds of life beginning, but we know it happened at least once. We know that the structure of our universe seems to favor the development of autocatalytic systems, feedb

Which tells us nothing except that it is possible for life to exist. The fact that life exists here tells us absolutely nothing about the likelihood of life arising apart from its being greater than zero because for obvious reasons we are sampling from a biased distribution, being alive ourselves.:-)

> Do you have any idea how many billions of stars are in our galaxy, and how many billions of galaxies are in the observable universe?

As it happens, yes. But I also know that combinatorial explosions [wikipedia.org] can generate numbers vastly larger than the number of things in the physical universe and the number of ways of arranging matter is described by a combinatorial explosion. Who knows how many of those combinations involve life, but it has the potential to be incredibly small. Small in a way that the size of the universe doesn't touch in bigness.

> If you are saying, "no one knows for sure. Don't say you're sure the chances are good if you can't prove they are," then that is certainly valid.

I've watched the astronomical community (from both the inside and as a layperson) go from not knowing for sure whether there were planets outside of the solar system to being able to routinely detect exo-planets with off-the-self equipment [www.ursa.fi] within 10 years.

I can't help but wonder how long it'll take till we have the same leap for detecting life once we know exactly what we're looking for. I'm hoping it'll be sooner rather than later.

There is a great book that anyone interested in this question should read: Rare Earth [amazon.com].

It is a very well-researched book that goes into great detail on all the different terms of the drake equation (and a few extra terms) and shows what the best scientific evidence suggests are the actual values for those terms. The bottom line of the book is that single-celled life is probably incredibly common, it's probably everywhere. Life that's big enough for you to actually see is probably pretty rare. Intelligent life is very rare, and technological civilizations are practically a miracle.

So by that definition, even if there are billions of civilizations, if the ratio is 1/10000000000000 then I don't think you can call it common.

Anyway, the grandparent post asked, "who believes in ET" and I think that a scientific answer: ET is out there, but maybe not even in our galaxy. So we are very very unlikely to ever find any life that we can talk to. The question that people

Yeah, but if we hypothesize one intelligent, technological civilization every 1,000,000 years for every 10 galaxies, that's still a whole lot of technological, intelligent civilizations. Apparently, the universe is really f'ing big. I recall when my astrophysics prof showed us a "map" of the universe and the "great wall" of galaxies.

if they're so far outside our light-cone that we'll never come into contact with them.

Assuming we can hold our civilisation together, it's still going to take us a friggin' long time to explore a single galaxy that's 100,000 lightyears across, with 200-400 billion stars in it. Even if there are thousands of intelligent races in the Milky Way, it might still take us a million years to find even one.

And if we're alone in this galaxy, the nearest one is 2 million lightyears away. Who's going to volunteer to

Actually, this doesn't even say as much as you think.For starters, heh... why is it any surprise that water exists? We already know that hydrogen is pretty much everywhere. (Just look at all those main sequence stars.)

And we already know that oxygen forms everywhere. Just look at the CNO cycle [wikipedia.org], again, pretty typical of main-sequence hydrogen-fusing stars. A percentage of it ends up staying oxygen -- or for that matter C, N or F, and occasionally all the way to iron and nickel -- so even a helium flash in a

Water may not be a big surprise however oxygen in the atmosphere (especially a hot atmosphere) will tend to bond with other atoms fairly quickly (oxidization). If O2 is still present in the atmosphere in large quantities after millions of years then it points to something constantly renewing it. Here on Earth that "something" is life, I have no idea what that "something" could be on the "hot jupiter" exoplanet.

But don't go looking for little green men. You might remember HD209458b as a 'hot Jupiter' that boils under the glow of its very nearby star."

Where there is hot water, there are saunas. Where there are saunas, there are tourists. Thus this remote planet has life, and most likley drinks with little umbrellas (or "snotzwathctls" as the local dialect probably refers to them).

We don't. I could dig up some papers for you on other potential biomarkers. They can be as esoteric as sharp lines on the surface that shift seasonally but whose spectral signature doesn't match up with materials that you would expect a phase change for.Also, O2 is no sure biomarker. Europa has an abiotic O2 atmosphere, albeit extremely thin. A "water world" (earthlike planet with no solid surface, only a giant global sea) could do it: ionizing radiation from the star separates 2 H2O into 4H + 2O, which

Also RE your sig - that's not an internet thing. In the newspaper and publishing business we've been using one space for decades [wikipedia.org]. Don't blame us if your middle-school teacher taught you wrong.

nothing survives at 600 degrees F. That is the temperature of the vent, and is strictly a sterile environment near the opening. The stuff that lives around the vents lives where the cold seawater and the vent liquid mix.

Maximum temperature for microbial life at pressure is closer to 200 degrees F or 90C. Similar to Thermus aquaticus in yellowstone, an extremophile that lives above 70C.

Sure bacteria live inside sea vents and even in nuclear reactor cores. Many of these don't even need oxygen (so using oxygen as an indicator of life is ill informed). Tube worms and other animals found near the vents don't live inside the vents, they live around them where the water is a lot cooler (way less than 100C).

Actually, using free oxygen in the atmosphere as an indicator of life is a good idea - if I remember correctly, unless there is some source replenishing it, doesn't free oxygen tend to bond with other stuff?

Sure it wouldn't be a slam dunk, but it'd be something that ought to be worth looking into.

I'm asking for some discussion on this subject. A lot of people look at extremophile organisms and take that as evidence that life as we know it ( carbon-based DNA/RNA cells ) is hardy, and can arise in many places -- hot places, cold places, frozen places, boiling places, nuclear reaction chambers, outer space, solid rock, etc., etc.

Personally, I lean toward that idea that life can only *originate* in a small window of 'specs' ( such as 70-100* F, in water, with plenty of amino acids floating around ),

**unless** they had Earth-like conditions at some point in the past, where life originated.

Recall the "programming error" in the survey ramrobots of Niven's Known Space: you only need those Earth-like conditions at one spot, not over the whole planet. Maybe there's the local equivalent of a Mt. Lookitthat [oinc.net].

Read the article, it deals with your question quite nicely: "'It now appears that the deep-sea hydrothermal vent environments are akin to those under which life on earth first arose,' Adams said." In other words, this seems to be the place where life started, not the other way around.To turn your question around: what makes the 70-100F range so special that life has to originate there? Liquid water? Exists in plenty of different fashions at different temperatures. Stable chemistry? Same. All in all, the ven

Well, I'm not particularly attached to the 70* F, water, etc. I could go for undersea thermal vents. I just wonder if life is hardy, and capable of arising any old place, or if original life needs a special set of circumstances. The reason I chose 70* F and water is because of those experiments that showed basic proteins assembling when some scientist zapped electricity into water with amino acids.
I may be wrong, but I believe that naked DNA and the basic amino acids and proteins can survive for a long ti

The reason I talk about DNA evolving first is because they sort of are the definition of life. Sure, membranes can form, but they're not really alive until they start metabolizing and reproducing. So to have life as we know it, we have to have something moderately complex, i.e. proteins or DNA. Membranes alone are not life.

Sure, that membrane is a start, but does it really protect against radiation and heat that well? Or does it serve just as a container for DNA, keeping it from being all slutty and rec

DNA as we know it melts at about 80 C.Sure, you can have some small evolutionary deviation in primitive organisms such as bacteria, allowing them to survive maybe a bit more (such as the extremophile vent-dwellers that live in 90C), but you'd need some fundamentally different data-storage-&-access machinery and molecular-assembly machinery to facilitate something that resembles life, if you want to stray further outside that range.

maybe you (or a creative bacterium) can come up with a very small icebox

sure, you could take Earth-life and transport it there. but the other side of that equation is, can life evolve on that planet. There are a couple of theories about how life got started on Earth. One is that it came here on comets. Another (this is from Dawkin's book, The Blind Watchmaker) is that life starts in streams with silicate crystals in clay, and that's not something you're likely to find on a hot jupiter.It turns out that evolution is easy, but genesis is hard. Remember, scientists have manag

There are other systems of life possible, without water, so long as they meet our definitions of life. Im always suprised by this very anthropocentric ('terrapocentric'?:) approach for the requirements for life...

There are other systems of life possible, without water, so long as they meet our definitions of life. Im always suprised by this very anthropocentric ('terrapocentric'?:) approach for the requirements for life...

Well, of course it's life as *we* know it. We don't know anything else, and trying to seriously imagine something which is of a completely different nature than your own is, at best, wild assed speculation.

Sure, you could posit a life form based on damned near anything -- but without any actual s

Just tell the US government there's oil up there and see how well funded NASA becomes.

No, really. Does that little bit of sophistry have to get trotted out every time a topic like this comes up?

Let's try something else...

"Just tell Hollywood that the planet is really hot, and celebrities will donate millions of dollars and have concerts to raise money for NASA to save the bears that may or may not live there, including a really nice concert somewhere in a nice town in the Great Plains, which um...

You're missing the point! I know it's a troll. I'm campaigning for newer, better, more entertaining trolling. I mean, if someone has to troll, can't they at least update their shtick? I'm just trying to help, here.